1. Field of the Invention
The present invention relates to an organic light emitting display device, and more particularly, to an organic light emitting display device with improved lifespan by reducing resistance at an interface between an emitting layer and a hole transport layer or an electron transport layer that is formed adjacent thereto.
2. Discussion of the Related Art
Image display devices, which display a variety of information on a screen, are a core technology of information and communication and are becoming increasingly thinner, lighter, more portable, and higher in performance. Thus, organic light emitting device (OLED) display devices, which display an image by controlling light emission of an organic emitting layer (EML), have received attention as a flat panel display device that may address problems in terms of weight and volume which occur in cathode ray tubes (CRTs).
OLEDs are self-emissive devices including a thin EML between electrodes and can be fabricated as a thin film with a thickness similar to that of paper. In particular, an OLED includes an anode, a hole transport layer (HTL), a hole injection layer (HIL), an EML, an electron injection layer (EIL), an electron transport layer (ETL), and a cathode.
As such, an EML is formed between an HTL and an ETL. In this regard, it is difficult for holes to move towards the EML due to an interface barrier between the HTL and the EML and it is difficult for electrons to move towards the EML due to an interface barrier between the ETL and the EML. Accordingly, lifespan of an OLED is reduced.